Introducing a new cat or kitten to your resident cat or dog can be quite nerve racking. You want them all to get on together and welcome the new feline into the house, but this seldom happens quite so easily - even though your reason for getting another cat may be to keep your resident cat company. It may not rush out and welcome the newcomer with open paws! Careful introductions can help to smooth the way towards harmonious merging of animals - controlling the situation rather than leaving the animals to sort it out for themselves will give a much better chance of a smooth meeting and the best possible start together.
Remember that cats do not need to be social creatures - unlike the pack-orientated dog they function happily on their own without a social structure around them. They are unlikely to feel the 'need' for a companion even though you would wish to have another cat around. You cannot force cats to like each other - some will live with a newcomer easily, others will never get on or they may just manage to live alongside each other in an uneasy truce - you can only try. However, if there is no competition for food or safe sleeping places (as in most good homes) then cats will accept each other eventually and some will even seem to form close bonds with one another. While it may be a matter of feline choice as to whether cats get on, how you introduce a new cat or kitten into your home and to a resident cat or cats can make the difference between success or failure. Once a relationship becomes violent or very fearful and the cat feels threatened it can be very difficult to change the behavior patterns. Thus careful introductions which prevent excessive reactions and taking things slowly is vital. Here are some factors involved in bringing cats together successfully:
Adults or kittens? A kitten is less of a threat to a resident cat than an adult cat because it is still sexually immature. It can also be better to g,et a kitten of the opposite sex to the resident cat to minimize competition. Neutering helps to remove most of such problems, but may not eliminate them altogether. If you are getting an adult cat again it can be better to bring in one of the opposite sex.
Timing Choose a quiet time when the household is calm - avoid festivities, parties, visiting relatives or friends and find time to concentrate on calm reassurance for both cats.
Smell is important Remember that scent is the most important of the cat's senses in terms of communication and well-being. You can try and integrate the new cat into your home and make it less alien by getting it to smell of 'home' before you introduce it to the resident cat. To do this stroke each cat without washing your hands and mix scents. You can also gather scents from around the cat's head by gently stroking it with a soft cloth and dabbing around your home and furniture. Likewise letting the cat get used to the new smells of the house and another cat before the initial meeting can make it more tolerable. For this reason it can be very useful to delay letting cats meet for a few days or even a week. During this time keep them in separate rooms allowing each to investigate the other's room and bed without actually meeting.
Using a pen or carrier for introductions It is up to you to make both the new cat and the resident feel as secure as possible and prevent the newcomer from being chased or threatened (or occasionally the other way round). Problems can arise if initial meetings are allowed to deteriorate into a fight or chase. The best way to avoid this is to use a kittening pen for initial introductions. Kittening pens are metal mesh pens about 1m by 0.75m by 1m high with a door which can be left open or shut securely. The cat inside can see what is going on around it but feels safe inside its 'den'.
You can put a blanket over the top initially to make the cat feel more secure if you think it feels vulnerable. The pen allows the cats to see each other, sniff through the bars and have a hiss and moan at each other without any attack or intimidation. The bars allow them to be close together but provide protection at the same time. If you have taken on a new kitten then it can be very useful to use the larger pen as a base for the kitten to be kept in initially. Introductions can be made using the pen and you can shut the kitten in with its bed and litter tray if you are going out and don't want to leave it where it can get into mischief or danger. The kitten can be shut in the pen at night (ensure water is available) with the other animals in the same room and they can get used to each other in safety. If you can't get hold of a pen or crate then you can use a cat carrier or basket for initial introductions. Of course you won't be able to use it as a den to shut the cat or kitten in for long periods because it is too small, but it will be better than nothing.
Place the new cat or kitten in the pen/carrier and let the resident cat come into the room. If you are using a cat carrier place it above ground level so the cats are not forced into direct eye contact with each other - this can cause aggression. Let the resident cat come into the room and give it attention and calm reassurance. If the cat decides to run away without investigating the new cat do not force meetings but accept that things may take a little time - this is probably the type of cat which will not initiate aggressive meetings but will stay out of the way and gradually accept the new cat in the household over time. If the cats show signs of aggression, distract them with a noise and then praise them for quiet encounters. You can use tit bits to encourage the cats to stay near each other and accept the other's presence and make it a positive experience - you want the cats to associate each other with pleasant happenings, not shouting or chasing. If you are using a large pen then you can allow the resident cat free access at times when the kitten/cat is in the pen over a number of days so that they gradually get used to each other. If you are using a carrier then you will need to be a little more proactive and orchestrate frequent meetings. With both methods you can start to feed the cats at the same time, the resident outside and the new cat inside the pen or carrier on the floor. Throughout this process there may be some hissing and spitting but this should gradually change into curiosity and gradual acceptance - this may take several days or weeks, depending on the individual cats.